The present invention relates to a cutting insert intended to be carried by a cartridge in a rotatable milling cutter body, whereby a major part of the periphery of the cutting insert is round.
Milling cutter tools are generally known in which insert-carrying cartridges are placed around the peripheral envelope surface of a cutter body. Depending upon how many cutting inserts the cutter body comprises, it is denoted as a coarse, close or extra-close pitch milling cutter. For face- and square shoulder milling in, for instance, the motor industry, a very precise positioning of the cutting edges is required, both in absolute terms and relatively to the other cutting edges in the milling cutter. Thus, the axial height difference between two cutting edges should not exceed a few .mu.m in order to attain the required surface smoothness.
In copending U.S. patent application Ser. No. 08/233,332 filed Apr. 26, 1994 (corresponding to Swedish Application No. 9301399-3) a construction is described for attaining a very accurate axial and radial position of the cutting edges in a milling cutter, which application is hereby incorporated herein by reference. According to that application, a milling cutter primarily for aluminum machining is formed with grooves milled in the envelope surface, in which grooves are mounted insert-carrying cartridges and spacer plates. These cartridges and spacer plates include serrated surfaces for mutually independent fine adjustment axially and radially.
Besides axial and radial adjustment, also the so-called angle of the parallel land has to be finely adjusted because this angle also has a great importance for the achieved surface smoothness. The angle of the parallel land is defined as the angle between the cutting edge of the parallel land and the produced surface on the workpiece. In order to make possible an adjustment of the angle of the parallel land, according to prior art the cutting insert has been mounted in a so-called cradle, which can be turned until the desired angle of the parallel land has been attained (see for instance German Document 31 40 905). However, this construction has the inconvenience that it comprises a number of separate parts and thus is rather complicated. Furthermore, the axial fine adjustment of the cutting insert is rendered difficult, since a further boundary line is created, viz. the line between cradle and cartridge. Moreover, such constructions cause instability because separate parts are mounted upon another in order to make possible a fine adjustment of the cutting inserts, whereby measure tolerances are superposed.
Thus, one object of the present invention is to make possible a quick and accurate fine adjustment of the angle of the parallel land of each cutting insert.
Another object of the present invention is to make possible an adjustment of the angle of the parallel land with as few separate parts as possible.
A further object of the present invention is to permit a movement of the cutting insert in its insert pocket without altering the preset clamping force, which is of utmost importance for a safe and stable positioning of the insert in the insert pocket.